Understanding the most efficacious products will allow clinicians to best communicate to patients and consumers the safest products on the market to reduce adverse events, including microbial keratitis, during contact lens use.

Microbial keratitis (MK) is an eye infection caused by opportunistic bacteria or fungi, which may lead to sight-threatening corneal ulcers. These microorganisms can be introduced to the eye via improper contact lens usage or hygiene, or ineffective multipurpose solutions (MPSs) to disinfect daily wear contact lenses. Thus, the patient’s choice and use of these MPSs is a known risk factor for the development of MK. It is then critical to determine the efficacy of popular MPSs against ubiquitous ocular microorganisms. Therefore, we compare the efficacy of nine major MPSs on the global market against four different microorganism species, and with four different common contact lenses. In accordance with International Standards Organization protocol 14729 and 18259, the microorganisms were inoculated into each MPS with and without contact lenses, and held for the manufacturer’s disinfection time, 24 h, and 7 days after challenge with Serratia marcescens or Fusarium spp. Plates were incubated for 2–7 days and plate counts were conducted to determine the number of surviving microorganisms. The majority of MPSs demonstrated significantly higher disinfection efficacies without contact lenses. Broadly, among the microorganisms tested, the OPTI-FREE products (Puremoist, Express, and Replenish) maintained the highest disinfection efficacies at the manufacturer’s stated disinfection time when paired with any contact lens, compared with other MPSs. These were followed closely by RevitaLens and renu Advanced. MPSs containing dual biocides polyquaternium-1 and myristamidopropyl dimethylamine possessed the highest disinfection efficacy against multiple ocular pathogens.

Acanthamoeba keratitis is a serious ocular infection which is challenging to treat and can lead to blindness. While this pathogen is ubiquitous and can contaminate contact lenses after contact with water, its habits remain elusive. Understanding this organism’s natural behavior will better inform us on how Acanthamoeba colonize contact lens care systems. Acanthamoeba trophozoites were allowed to adhere to either a glass coverslip or non-nutrient agar (NNA) within a flow cell with nutrients (Escherichia coli or an axenic culture medium (AC6)) or without nutrients (Ringer’s solution). Images were taken once every 24 s over 12 h and compiled, and videos were analyzed using ImageJ Trackmate software. Acanthamoeba maintained continuous movement for the entire 12 h period. ATCC 50370 had limited differences between conditions and surfaces throughout the experiment. Nutrient differences had a noticeable impact for ATCC 30461, where E. coli resulted in the highest total distance and speed during the early periods of the experiment but had the lowest total distance and speed by 12 h. The Ringer’s and AC6 conditions were the most similar between strains, while Acanthamoeba in the E. coli and NNA conditions demonstrated significant differences between strains (p < 0.05). These results indicate that quantifiable visual tracking of Acanthamoeba may be a novel and robust method for identifying the movement of Acanthamoeba in relation to contact lens care products. The present study indicates that Acanthamoeba can undertake sustained movement for at least 12 h with and without nutrients, on both rough and smooth surfaces, and that different strains have divergent behavior.

Both solutions eliminated or reduced populations of FDA/ISO compendial bacteria and fungi as well as clinically relevant microorganisms and Acanthamoeba trophozoites and cysts. The addition of EOBO-21 to the 3% H2O2 lens care solution had no impact on antimicrobial activity.

The extraction of chromium (VI) into tri-n-butyl phosphate from aqueous perchloric. sulphuric, nitric, hydrochloric, and hydrobromic acid has been studied at both tracer and macro-concentrations. With hydrochloric and hydrobromic acid, the species in the organic phase is HCr0,X (X = C1, Br) ; in the other acids, the organic phase contains H,Cr,O,.The number of solvent molecules solvating the extracted species in the organic phase has been measured; the values found are discussed in terms of the H,O,+ ion.-4 NUMBER of papers in the literature have been concerned with the extraction of chromium(v1) from aqueous solution by basic organic solvents, especially for analytical purposes. Solvents used include 4-methylpentan-2-one ( I ' hexone ") 1-4 and diethyl etlier.5 It should be emphasised immediately that the statement made by Weinhardt and Hixson,l that 4-methylpentan-2-one is a selective solvent for chromium(vI), is incorrect, both in the sense that chromium(v1) species can be extracted by a number of different basic organic solvents, and equally in that 4-methylpentan-2-one is known to extract many other elements. Various authors have reported the use of phosphoruscontaining solvents for this extraction.used trioctylphosphine oxide for the extraction of macro-amounts of chromium, and Specker and Arend and Shevchenko, Shilin, and Zhdanovs have discussed various aspects of the extraction by trin-butyl phosphate, a solvent which is of special interest because of its use in the industrial processing of nuclear fuels.The extraction of chromium(v1) has a number of peculiar features, arising from the multiple pH-dependent equilibria in the aqueous phase. In particular, two dibasic acids, chromic and dichromic, can in principle be extracted by basic solvents. We have studied the extraction of macro-and tracer amounts of chromium(v1) from hydrochloric, hydrobromic, sulphuric, perchloric, and nitric acid media by both pure tributyl phosphate and its solutions in an inert solvent (cyclohexane). In general, the results do not completely confirm some of the previous views on the mechanism of the extraction; also, additional equilibria involving chromium(v1) in the aqueous phase may now have to be postulated, White and Ross EXPERIMENTAL Materials.-Chromium trioxide and potassium dichromate were both of analytical grade ; recrystallised sodium dichromate dihydrate was used without durther purification. Reagent grade acids were used as supplied, except for hydrobromic acid which was shaken with 5% tributyl phosphate in chloroform to remove any traces of free bromine or HBr,. Water was ion-exchanged water which, for certain experiments, was distilled from alkaline permanganate. that used in tracer experiments was also pretreated with permanganate to remove any reducing impurities. Cyclohexane (May and Baker) was used without further treatment.Procedure.-In experiments involving macro-quantities of chromium, initially equal volumes (3--20 ml.) of aqueous and organic phases were shaken together in stoppered glass tubes. With hydroc...